I-X [Circulatory] means herbal iron. Iron is needed by the body to carry oxygen to the cells, where it is combined with glucose for energy production. It also must be present for protein metabolism. By combining herbs that provide natural iron with other elements needed to enhance absorption, a chelated form of iron is created that's more easily absorbed by the body. This formula is also a source of calcium, magnesium, manganese, phosphorus, silicon and zinc. Riboflavin, thiamine and vitamins A and C are also present. It contains: Red beet root Yellow dock root Red raspberry leaves Chickweed herb Burdock root Nettle herb Mullein leaves